Powerhead control in a power injection system

ABSTRACT

A dual head contrast media injection system performs a patency check or test injection, determining flow rate and/or flow volume from the programmed protocol. The tubing that connects syringes to a patient shares only a short common section near to the patient. Appropriate injection steps are taken to compensate for tubing elasticity. A wireless remote control and a touch screen control are provided, improving functionality and information delivery. The display brightness is controlled based on the ambient light, and the display panel includes a double swivel permitting re-orientation. The orientation of the display may also be controlled based on, e.g., the current step, the tilt angle of the powerhead, or a manual control. Furthermore, the display is customizable to identify the type of fluid (contrast, saline, etc.) on either side of the injector, to provide matched color coding, and to provide a folder/tab analogy for retrieving injection protocol parameters.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. applicationSer. No. 10/964,002, filed Oct. 13, 2004, entitled POWERHEAD OF A POWERINJECTION SYSTEM, now abandoned, which is related to application Ser.No. 10/964,003, filed Oct. 13, 2004, entitled POWER.HEAD OF A POWERINJECTION SYSTEM, now U.S. Pat. No. 7,507,221. The present applicationis related to co-pending and concurrently filed application Ser. No.11/073,915, entitled POWERHEAD OF A POWER INJECTION SYSTEM, nowabandoned, and the two divisional applications of application Ser. No.10/964,003, filed Oct. 13, 2004, entitled POWERHEAD OF A POWER INJECTIONSYSTEM, now U.S. Pat. No. 7,507,221. All of these applications arehereby incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to contrast media injector systems and,more particularly to improvements thereto.

BACKGROUND OF THE INVENTION

In many medical environments, a medical fluid is injected into a patientduring diagnosis or treatment. One example is the injection of contrastmedia into a patient to improve CT, Angiographic, Magnetic Resonance orUltrasound imaging, using a powered, automatic injector.

Injectors suitable for these and similar applications typically must usea relatively large volume syringe and be capable of producing relativelylarge flow rates and injection pressures. For this reason, injectors forsuch applications are typically motorized, and include a large, highmass injector motor and drive train. For ease of use, the motor anddrive train are typically housed in an injection head, which issupported by a floor, wall, or ceiling mounted arm.

The injection head is typically mounted on the arm in a pivotal manner,so that the head may be tilted upward (with the syringe tip above theremainder of the syringe) to facilitate filling the syringe with fluid,and downward (with the syringe tip below the remainder of the syringe)for injection. Tilting the head in this manner facilitates removal ofair from the syringe during filling, and reduces the likelihood that airwill be injected into the subject during the injection process.Nevertheless, the potential for accidentally injecting air into apatient remains a serious safety concern.

In addition to the injection head discussed above, many injectorsinclude a separate console for controlling the injector. The consoletypically includes programmable circuitry which can be used forautomatic, programmed control of the injector, so that the operation ofthe injector can be made predictable and potentially synchronized withoperations of other equipment such as scanners or imaging equipment.

Thus, at least part of the injection process is typically automaticallycontrolled; however, the filling procedure, and typically some part ofthe injection procedure, are normally performed by an operator, usinghand-operated movement controls on the injector head. Typically, thehand-operated movement controls include buttons for reverse and forwardmovement of the injector drive ram, to respectively fill and empty thesyringe. In some cases, a combination of buttons is used to initiatemovement of the ram or to control ram movement speed. The injector headalso typically includes a gauge or display for indicating injectionparameters to the operator, such as the syringe volume remaining, forthe operator's use when controlling the injector head. Unfortunately,operators have found it cumbersome to use the hand-operated movementbuttons and to read the injector head gauges and displays, for severalreasons, not the least of which is the necessary tilting of the injectorhead between the upward, filling position to the downward, injectionposition, changing the positions of the hand-operated movement buttonsrelative to the operator, and at some tilt angles rendering the gaugesor displays difficult to read.

In many applications, it is desirable to use an injector with multipledifferent syringe sizes. For example, it may be desirable to use asmaller syringe for pediatric use than for adult use, or where aparticular procedure requires a smaller volume of fluid. To facilitatethe use of different syringe sizes, injectors have been constructed withremovable faceplates, where each of the various faceplates is configuredfor a particular syringe size. Typically, the injector is able to adjustinjection parameters by detecting which faceplate is mounted to theinjector, for example using a magnetic detector mounted to the frontsurface of the injector housing to detect the presence or absence of amagnet in the faceplate. Unfortunately, the necessity of incorporating amagnetic detector into the outer housing of the injector head increasesthe complexity and expense of manufacturing the injector head.

Recently, one development in power injectors has been the introductionof dual headed injectors, that is, an injector with two drive systemsand mountings for two syringes. The software for the injector providesfor independent control of these drive systems using both manualcontrols and programmed injection routines in response to a storedsequence. Such dual headed injectors allow multiple fluids to beinjected during a sequence without changing a syringe or otherequipment.

Regardless of the benefits of current power injector systems, whethersingle head or dual head, improvements and advances in this fieldcontinue to be desirable goals and will ensure that such equipmentbecomes easier to use, increase in functionality, and become morereliable and efficient in operation.

SUMMARY OF THE INVENTION

Accordingly embodiments of the present invention relate to improvingpower injectors that are used to inject contrast media and other fluidsin a patient or animal.

One aspect of the present invention relates to a display, such as theconsole or powerhead, of the injector system accommodating differentambient light conditions. For example, the display elements such as LCDscreens and LED lights can be controlled such that their relativebrightness levels are dependent on the ambient light conditions.Operator override functionality can be provided as well.

Another aspect of the present invention relates to a touch screeninterface for the powerhead of the contrast media injector system. Thetouch screen display can be driven from software so that it isconfigurable and not dependent on hardwired switches, LED indicators or7-segment displays. The powerhead can therefore, provide the samefunctionality as the console display, thereby eliminating the console ifdesired. In addition to more data and more controls being available atthe powerhead, help instructions and other contextual assistance can beprovided to help the operator run the equipment.

Yet another aspect of the present invention relates to a display for adual head injector system that displays information about both syringesand fluid simultaneously. The display of the powerhead is color-coded sothat information about one syringe is visually distinct from informationabout the other syringe. For additional ease-of-use conventional colorassociations can be used such that a purple display refers to contrastmedia, yellow refers to saline, and black refers to air.

In accordance with another aspect, additional ease-of-use features areincluded in the display of stored protocol information, by use of afolder-tab analogy for managing numerous stored protocols.

Still a further aspect of the present invention relates to a remotecontrolled powerhead. A conventional powerhead drive mechanism andsyringes are augmented to include a receiver for receiving a controlsignal from a remote device. In response to the control signal, thepowerhead operates the syringe ram appropriately.

One additional aspect of the present invention relates to a dual headinjector that utilizes tubing in which the fluid paths remain separateuntil substantially at the patient. By utilizing this type of V-tubing,the elasticity of the fluid delivery components (e.g., syringe, tubing,etc.) can be easily accommodated and there is reduced lag time inadministration of a desired fluid to a patient.

One more aspect of the present invention relates to performing a patencycheck using a dual head injector system. In accordance with this aspectof the invention, a saline injection is enabled and performed prior toexecution of the stored protocol of an injection, at nearly the sameflow rate and volume as the upcoming media injection, to ensure thatextravasation does not occur. This method may be implemented in softwarethat retrieves the flow rate and other information about a selectedprotocol and controls the saline patency injection based on thoseparameters.

A related aspect of the present invention relates to a test injectionfeature. In accordance with this aspect, a test injection is performed,initially using the same fluid and initial flow rate as an storedprotocol of an injection, to enable the user to determine thesuitability of that flow rate and also determine the timing associatedwith the injection such as the delay time for the injected fluid toreach an area of interest of the patient.

It will be appreciated that both the test injection and patency checkhave common characteristics that distinguish them from normalprogramming of an injector. Specifically, both are an injection that isseparately enabled from the stored injection protocol to be administeredto the patient, and both are separate from the stored injectionprotocol, i.e., they may selectively be conducted, or not, at theoperator's discretion. Thus, the operator need not perform a patencycheck or test injection, but has the ready option to do so withoutaltering a stored injection protocol. While the patency check and testinjection are thus functionally and operationally separated from astored protocol, they are nevertheless programmatically controlledinjections, and use parameters that may be derived from the later,stored injection protocol, e.g., the flow rates or use of fluids ismodeled after the planned injection. Because the test injection andpatency check are programmatically controlled injections, they mayaccurately mimic the stored injection protocol in the relevant aspects,without the effort of human involvement and the possibility for humanerror. Furthermore, because they are programmatically controlled, it ispossible to calculate the fluid requirements of the patency check ortest injection, which may be combined with the planned subsequentinjection to ensure that there is sufficient injectable fluid available,thus ensuring that time is not lost re-filling the injector (which mayinvolve re-entering the scanning room after it has been sealed) as mayoccur if a patency check or test injection is manually performed.Finally, in the context of a dual headed injector, a test injection orpatency check, because it is programmatically controlled, may includefunctionality to automatically return the injector tubing to anappropriate initial state, e.g., a state in which the tubing is filledwith saline or contrast media, or a mixture, as the operator andphysician prefers for the imaging procedure.

Another aspect of the present invention relates to a mount for a displayscreen on an injector that permits the screen to be positioned flushwith a surface of the injector or to be moved to a position extendingfrom the surface of the injector. In the described embodiment the mountprovides a double swivel permitting the screen to be swivelled away fromthe injector surface and pivoted about its axis, thereby facilitatingvisibility of the screen for numerous possible injector and operatorpositions.

A related aspect of the present invention involves programming of thepowerhead to orient the content on the display automatically to anappropriate orientation and/or re-size that content based upon thecurrent step in an injection sequence. This aspect may also be combinedwith sensors relating to the orientation of the display. For example, ifa sensor is included in the mounting mentioned above, the display may beautomatically re-oriented in response to tilting of the display awayfrom the injector. Further, if an Earth gravitation sensor is includedin the injector, the display may be automatically re-oriented inresponse to tilting of the injector relative to gravity, e.g. tiltingupward for filling and downward for injecting.

A further aspect of the present invention relates to an injectorpowerhead for injection from first and second syringes, which maycontain fluids of two different types, in which the injector permits anoperator to identify the type of fluid contained in the first or thesecond syringe, thus enabling the operator to use either syringelocation for either type of fluid, at the operator's discretion.

It will be appreciated that principles of the present invention areapplicable to the injection of contrast media into a patient to improveCT, Angiographic, Magnetic Resonance or Ultrasound imaging, or any otherapplication involving injection of fluids using a powered, automaticinjector.

The above and other objects and advantages of the present inventionshall be made apparent from the accompanying drawings and thedescription thereof.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention and,together with a general description of the invention given above, andthe detailed description of the embodiments given below, serve toexplain the principles of the invention.

FIG. 1A illustrates a power injector system according to the principlesof the present invention, and FIG. 1B illustrates the components of thepowerhead of that system.

FIG. 2 illustrates a block diagram of a display system that controls thebrightness of its display elements based on ambient light conditions inaccordance with the principles of the present invention.

FIG. 3 depicts a flowchart of an exemplary algorithm useful with thesystem of FIG. 2.

FIGS. 4A-4E illustrate a series of exemplary interface screens for atouch-screen display of a powerhead in accordance with the principles ofthe present invention.

FIG. 4F illustrates a swivel mount for an injector powerhead displayscreen in accordance with principles of the present invention.

FIGS. 5 and 6 illustrate an exemplary powerhead display screen for adual head system that correlates tubing color and display icons andcolors with each other in accordance with the principles of the presentinvention.

FIG. 7 illustrates a remote controlled powerhead in accordance with theprinciples of the present invention.

FIG. 8 illustrates exemplary V-tubing to connect a dual injector headsystem to a patient in accordance with the principles of the presentinvention.

FIG. 9 illustrates an exemplary end fitting for the tubing of FIG. 8.

FIG. 10 illustrates an exemplary cross-section of the tubing of FIG. 8.

FIG. 11 depicts a flow chart of an exemplary method to perform a patencycheck with a dual head injector system.

FIG. 12 depicts a flow chart of an exemplary method to perform a testinjection with an injector system.

FIG. 13 depicts an exemplary display screen for a dual head injectorsystem used to perform a test injection method.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring to FIG. 1A, an injector 20 in accordance with the presentinvention includes various functional components, such as a powerhead22, a console 24 and powerpack 26. Syringes 36 a and 36 b are mounted tothe injector 20 in faceplates 28 a and 28 b of the powerhead 22, and thevarious injector controls are used to fill the syringe with, e.g.,contrast media for a CT, Angiographic or other procedure, which media isthen injected into a subject under investigation under operator orpre-programmed control.

The injector powerhead 22 includes a hand-operated knobs 29 a and 29 bfor use in controlling the movement of the internal drive motors engagedto syringes 36 a and 36 b, and a display 30 for indicating to theoperator the current status and operating parameters of the injector.The console 24 includes a touch screen display 32 which may be used bythe operator to remotely control operation of the injector 20, and mayalso be used to specify and store programs for automatic injection bythe injector 20, which can later be automatically executed by theinjector upon initiation by the operator.

Powerhead 22 and console 24 connect through cabling (not shown) to thepowerpack 26. Powerpack 26 includes a power supply for the injector,interface circuitry for communicating between the console 24 andpowerhead 22, and further circuitry permitting connection of theinjector 20 to remote units such as remote consoles, remote hand or footcontrol switches, or other original equipment manufacturer (OEM) remotecontrol connections allowing, for example, the operation of injector 20to be synchronized with the x-ray exposure of an imaging system.

Powerhead 22 is mounted to a wheeled stand 35, which includes a supportarm for supporting powerhead 22 for easy positioning of powerhead 22 inthe vicinity of the examination subject. Console 24 and powerpack 26 maybe placed on a table or mounted on an electronics rack in an examinationroom. Other installations are also contemplated however; for example,powerhead 22 may be supported by a ceiling, floor or wall mountedsupport arm.

Referring to FIG. 1B, details of the powerhead 22 can be seen. In FIG.1B, specific content can be seen on touch screen display 30 illustratingthe two syringes and their status, as well as a protocol of injectionsteps to be used in conjunction with those two syringes.

Although the powerhead 22 discussed herein is a dual head injector,embodiments of the present invention explicitly contemplated single headinjectors as well.

Referring to FIG. 2, an optical sensor 262 is included on one of theinternal circuit boards within the injector powerhead housing 30 and issituated near a window 263 or other opening that allows it to detectambient light levels. Such an optical sensor 262 would typically be ananalog device that converts the light level detected into a voltage orcurrent signal. After being converted via an analog-to digital converter(ADC), this signal could then be used by a microprocessor to raise orlower the brightness levels of the display. The control algorithm forcorrelating detected light levels with a display brightness setting maybe selected according to a variety of methods. For example, thebrightness and detected light levels may be linearly correlated.However, if the optical sensor 262 has a non-linear detection curve thenan appropriate correlation formula can be used to change the brightnesslevels. Additionally, the brightness changes might occur at a limitednumber of predefined steps or, alternatively, cover a nearly-continuousspectrum of brightness settings. Thus, one of ordinary skill wouldrecognize that within the scope of the present invention, there are avariety of functionally equivalent methods for adjusting the brightnessof the power injector's display based on the ambient light conditions.

The methods of adjusting the brightness vary with the type of display.For example, brightness of LED's 270 on the powerhead may be adjusted byadjusting the duty cycle of the signal driving the LED. An LCD drivercircuit 268, on the other hand, could use a pulse-width modulatedsignal, or a DC voltage level, to control its brightness setting. Theintensity control circuits 264, 266, therefore, may be differentdepending on the type of display (e.g., 268, 270) being controlled.

An exemplary algorithm for controlling the display of either thepowerhead 30 or the console 32 is depicted in the flowchart of FIG. 3.The sensors and control circuitry are conventional in nature and one ofordinary skill will recognize that a variety of functionally equivalentcircuits could be used to generate the appropriate control signals. Instep 302, a sensor is used to detect an ambient light level in theenvironment where the injector equipment is being used. Then, in step304, this detected level is converted into a brightness setting for thedisplay. This conversion process may include simple analog-to digitalcircuitry or use a microprocessor with accessible memory that correlatesa detected level to a display brightness according to stored settings inthe memory. The conversion process may utilize operator inputs tooverride default behavior or operate automatically without consideringoperator inputs. Ultimately, in step 306, the display hardware iscontrolled according to the brightness setting. The LEDs of a particulardisplay may have their own control circuitry that operates themaccording to the brightness setting, and an LCD screen or other displaymay have its own separate control circuitry operating it appropriately.

Conventional powerheads for injectors have included only enough controlsto implement a limited amount of functionality as compared to theconsole of the injector system. The powerhead controls were typicallylimited to moving the syringe ram and enabling, starting and disablingan injection protocol. The information displayed by the powerhead duringan injection was also limited in nature. The console on the other handhas a larger display and more controls that provided additionalfunctionality. Protocol selection and entry, saving and editinginjection and syringe parameters, patient contrast volume, injectionhistory, injection phase information and delays, syringe parameters,interface information, instructions and help screens, etc. are allfunctionality typically provided through the console but not thepowerhead.

In contrast to the conventional injector system, as just described,embodiments of the present invention include a powerhead that does notrequire a console. Through screens on the powerhead an operator is ableto control everything involved in an injection sequence. As oneadvantage of such a system, the up-front cost of the injector without aconsole is reduced. Also, the ability of the display of the powerhead todisplay more and better information, help screens and other functionsallows an operator to more efficiently operate and to more quickly learnhow to operate the powerhead via a touch screen. Instead of the controlson the powerhead being hard-wired switched and buttons, the displaycould be a touch screen that presents a user interface that is easilyreconfigurable and more robust.

Referring to FIGS. 4A-4F, an injection protocol will be described fromthe operator's perspective. However, unlike conventional injectorsystems the interface screens described with respect to these figuresare provided by a touch screen display 30 at the powerhead. The mainoperating screen is illustrated in FIG. 4A. Box 200, which is associatedwith an iconic representation 201 of the powerhead, identifies thecurrent volume of contrast media in the A syringe. Box 202, which isassociated with an iconic representation 203 of the syringe, identifiesthe current volume of contrast media in the B syringe. Box 204identifies the pressure limit pre-selected by the operator for theprocedure, and box 206 identifies a scan delay (in seconds), which isthe delay from the time the operator initiates an injection (either withthe hand switch, a key on the console or a button on the powerhead)until the x ray or magnetic scan of the subject should begin (at the endof this delay, a microprocessor within the powerhead produces a toneindicating to the operator that scanning should begin; alternatively,scanning could be automatically initiated by a suitable electricalconnection between the scanner and injector). Box 207 identifies aninject delay (in seconds), which is a delay from the time the operatorinitiates an injection as noted above, until the injection as descriedby the protocol will begin, thus allowing time for the scanner to beinitiated before flow of contrast. In the illustrated situation, thesyringe A contains 158 ml of fluid, 73 ml of which will be used by thecurrently selected protocol, syringe B contains 158 ml of fluid, 83 mlof which will be used by the currently selected protocol, the pressurelimit is 20 psi and there is no scan or inject delay.

In the display illustrated in FIG. 4A, button 208 may be used to alterthe orientation of the display. Specifically, as seen in FIG. 4B, bypressing the screen at this button, the display may be reversed on thescreen to thereby facilitate the use of the injector in multiplepossible orientations.

As shown in FIG. 4A, a protocol comprises a number of phases; duringeach phase the injector produces a pre-programmed flow rate to output apre-programmed total fluid volume. The illustrated protocol has only twophases; however, other protocols which can be selected by the operatorhave multiple phases. The user can select protocols, enable aninjection, and otherwise navigate through display screens by pressingthe touch buttons of the display 30.

Regions 212 of the display identify the flow rates for the phases of thecurrent protocol, and regions 214 identify the volumes for thoserespective phases. The user may alter these parameters by pushing any ofthese regions, to move thereby to a protocol parameter entry screen,shown in FIG. 4C. On this screen the user may change and store the flow,volume and inject and scan delay values for the current protocol bypressing each of these values as displayed on the screen, and thenmoving the slide bar control shown in region 216.

From FIG. 4A, the operator may also enter a manual control display bypressing on the iconic representation of a syringe 201 or 203. At themanual control display, shown in FIG. 4D, the operator may manuallycontrol plunger movement. At this screen, the iconic representation ofthe selected syringe in box 200 of FIG. 4A is replaced with a fill-expelbar display 220. By pressing on this fill-expel bar display the motordrive for the selected syringe may be caused to advance or retractthereby to fill or expel fluid from that syringe.

Referring now to FIG. 4E, the display of stored injection protocols canbe described. Through the memory button 218 in FIG. 4C, the protocolmemory display seen in FIG. 4E may be viewed, where protocols may bestored and retrieved. Protocol memories are known in the art, however,one difficulty with the display of protocols in the prior art has beenthe limited space available to display a representation of a largenumber of protocols. For example, as seen in FIG. 4E, only eightprotocols can be adequately represented on the display, each associatedwith a customized named button 222 in the left hand column, andparameters displayed in the right hand column. To overcome thisdifficulty, in accordance with principles of the present invention, fivegraphical “tabs” 224 are also provided on the display. Each tab isassociated with different set of eight protocol storage locations 222,and the operator may move quickly between the tabs by pressing upon thetabs 224. In this way, forty protocols may be stored and quicklyretrieved while continuing to provide sufficient information regardingeach protocol on the screen. The tabs 224 may bear numbers or may haveuser-configurable names as are used with protocols, so that, forexample, one tab may contain protocols used with each of severaltechnicians or physicians.

The above description of an interface for an exemplary powerheadidentifies a number of specific features; however, the principles of thepresent invention apply to a variety of other touch-screen features thatmay also be provided. Indeed, a touch screen provides sufficientflexibility in the interface that certain embodiments of the presentinvention contemplate providing a complete interface at the powerheadsuch that a console is no longer needed for a power injection system.

U.S. Pat. No. 5,868,710, commonly assigned to the present assignee, isincorporated by reference in its entirety. That patent discloses adisplay screen for an injector powerhead that automatically detects theorientation of the powerhead and flips the output of the display screenaccordingly so that it is more readily readable to an operator.Embodiments of the present invention advantageously include suchfunctionality for the augmented display screen as described above.

Referring to FIG. 4F, in a further embodiment consistent with principlesof the present invention, the display screen 30 may be mounted topowerhead 22 by a swivel mount 238, permitting the screen 30 to bepositioned flush with a surface of the injector powerhead 22, or to betilted from the surface of the powerhead 22 as shown by arrows 240, andoptionally subsequently pivoted about mount 238 as shown by arrow 242,thus permitting screen 30 to be optimally positioned to permit controland operation of injector powerhead 22 for any number of variouspossible injector and operator positions.

The current orientation of the display as shown in FIG. 4F may bedetected by a sensor incorporated within the injector, so as tore-orient the display appropriately as the display is swivelled relativeto the injector head. Such a feature may be used in conjunction with theuse of a tilt sensor as described in the above-referenced U.S. patent toenable a rich interface selecting an appropriate initial screen displayorientation. Furthermore, screen display orientation may be responsiveto the current status of the injector in an injection sequence, e.g.,one orientation may be used when in a manual control mode as shown inFIG. 4D (when the injector is typically tilted upward for filling) and asecond orientation used when performing an injection protocol such asshown in FIG. 4A (when the injector is typically tilted downward forinjecting).

It will be appreciated that there are other possibilities forconfiguring the injector powerhead display in response to injectionsteps and/or tilt angle of the injector. For example, during an actualinjection sequence when the injector is armed, tilted down, and aninjection is enabled, the technician using the injector is often in aseparated control room far from the injector powerhead. Under suchcircumstances it may be beneficial to display, in a very large fontoriented for an injector tilted downward, the current injector flowrate, volume and/or pressure, potentially together with color coded,blinking or flashing regions or fonts, or graphical iconography, toindicate the injector status in a manner that will be visible by thetechnician from a great distance, so that the technician may watch thepatient during the procedure and still have basic feedback on theoperation of the injector without looking to the console.

If the console is included with the contrast media injector system, thenthe powerhead is a secondary control interface for the contrast mediainjector system. The computer, memory and executable applications thatare typically a part of the console would continue to be a part of theconsole and the powerhead would simply communicate with the console. If,however, the console were not included in the contrast media injectorsystem then the powerhead or some other component would need to beincluded that possessed the computational and storage capabilities toprovide such functions as on screen textual help, multiple touch screensthat are configurable to provide a clear user interface, protocolsetting and setup information, etc. that was typically provided by theconsole.

Turning to a different topic, injector powerheads have conventionallyincluded a single injecting head but dual head injectors are becomingmore prevalent as well. Typically, one syringe is used to deliver salineand the other is used to deliver contrast media (although other fluidsare used as well). Features that make these injectors safer, easier, andfaster to use are desirable; especially those that can be performedautomatically by control software within the powerhead.

The dual head injector powerhead 22 with display 30 discussed above, isdepicted schematically in FIG. 5 along with tubing and connectionsthereto. Each syringe 36 a, 36 b is connected to respective tubing 506,508 that eventually joins into a common tubing portion 510 that ends ata fitting 512 (e.g., Luer fitting) coupled to a catheter that deliversfluid to a patient.

The tubing 506, 508, may be colored to indicate the contents of thetubing or it may be clear. In either case, the display 30 includesgraphical information for an operator that indicates the fluid that isbeing delivered by each syringe 36 a, 36 b. An exemplary display isdepicted in FIG. 6 that may be part of the display screen 30. Onegraphical image of a syringe 602 and tubing 606 is provided on the leftwhile another graphical image of a syringe 604 and tubing 608 isprovided on the right. As shown, a respective fluid 610, 612 is shown ineach syringe 602, 604. In particular, as an injection protocolprogresses, the display 600 changes to reflect the fluid level changesand to reflect which fluid is being delivered to the patient (portion609 of FIG. 6).

To assist the operator in recognizing what fluid is being delivered fromwhich syringe, the display 600 color-codes the contents of each syringeand tubing to identify the fluid. For example, a clear color on thedisplay 600 may indicate that air is in a particular syringe and tubing.Coloring the fluid “red” on the display 600 may indicate that contrastmedia is in that syringe, while a different color (e.g., blue) indicatesthe presence of saline.

Such a colored display could also be used on a single head injector toindicate the status of different automatic functions. For example, thistype of graphical display including color information allows an operatorto easily and quickly determine if a syringe is full of air; when anempty syringe and tubing have been properly filled and purged, or when apre-filled syringe has been purged properly.

It will be noted that dual-head injectors have typically required an apriori selection of saline and contrast locations on the two heads, forexample, for consistency with the displays of the injector, a syringecontaining saline fluid would be required to be attached to the firstside of the injector and a syringe containing contrast media would berequired to be attached to the second side of the injector. An aspect ofthe present invention is to permit configuration of the injector suchthat displays presented on the injector can be made consistent with anycombination of fluid types on the injector. Specifically, an injector inaccordance with the present invention permits the operator to define thetype of fluid, and color coding thereof, on each of the A and B sides ofthe injector. Thus, the operator may use the injector with syringescontaining fluids of any two arbitrarily selected types, or with fluidsof the same types, and correspondingly configure the injector and itsdisplays to match the chosen application. Any arbitrarily selected fluidtype may also be used with any arbitrarily selected syringe size. Thisenables the operator to use either syringe location for any syringe sizeand any type of fluid, at the operator's discretion, without beingsubjected to confusingly inconsistent displays from the injector.Alternate color-coded tubing sets may also be provided for matching tothe selected injector displays.

In the dual head powerhead of FIG. 5, two different fluid tubes arecoupled with the injector powerhead 503 but, typically, there is onlyone fluid entry point at the patient. Thus, the two fluid tubeseventually merge together between the syringes and the patient. In thepast, Y-tubing has often been used in which the separate tubes mergerelatively near the syringes so that a single fluid tube exists for themajority of the tubing. The inherent elasticity of syringes allows backflow to the non-driven syringe during a pressure injection. Unlessprecautions are taken with common Y-tubing, a typical injectionproducing 150 psi will allow about 5 ml of the contents of the drivensyringe to be pushed into the undriven side where it will contaminatethat side. In the past, check valves have been used to prevent this, butsuch a solution introduces its own set of problems.

Also, Y-tubing has a lag time between supplying the two differentfluids. In other words, the entire contents of the Y-tubing sharedportion must be flushed of one fluid before a second fluid can bedelivered to the patient. While methods exist for addressing this issue,these methods require additional activity and input by an operator thatcomplicates and lengthens an injection routine.

FIG. 8 depicts a V-tubing arrangement in which the junction between thetwo tubings is relatively close to the patient's end. Two syringes 802,804 are used to deliver two different fluids to a patient. The syringe804 is coupled with an initial portion of tubing 806 and the syringe 802is coupled with a separate portion of tubing 810. Although theseportions of tubing 806, 810 merge externally, they retain separate flowpaths through a common portion of tubing 811. The tubing 811 terminatesat the patients end with a fitting 812 to deliver one of the fluids.

The cross-section of an exemplary fitting is depicted in FIG. 9. Thetubing 811 splits into separate portions 902, 904 that both couple tothe fitting 812. In particular, the portions 902, 904 couple to acentral cavity 816 such that fluid directed through the tubing sections902, 904 are delivered to the cavity 816. From the cavity 816, fluid isexpelled from the fitting 812 through an opening 814.

Even though the tubing 811 appears externally to be a single fluid tube,the principles of the present invention maintain the separate fluidpaths until the tubing 811 substantially reaches the fitting 811. FIG.10 depicts exemplary cross-sections that could be used to implementtubing 811. The cross-section 1002 is generally circular in nature withtwo passageways separated by a vertical wall. The cross-section 1004 issimilar to two circular tubes attached along a common side. Each crosssection may be formed from co-extruded plastic or by similar means andcan be color coded to help identify the intended contents of the tubing.

As mentioned, a typical power injector system includes inherentelasticity due to compression of the syringe plunger and the expansionof the syringe barrel. The shape and size of the plunger affects thisamount of elasticity as well. According to certain embodiments of thepresent invention, the un-driven side of the powerhead may be driven toa sufficient displacement to prevent the movement of fluid into thetubing on the undriven side due to elasticity. The amount of amounts offluid to drive from an un-driven syringe will be a function of thepressure used on the driven size and the type of syringe in use. In aclosed-loop approach, a measure of pressure and/or fluid flow in theundriven sized may be used to perform closed-loop control of the ram onthe undriven side to prevent flow into the undriven side due toelasticity. In an open-loop approach, measured values of typicalelasticity may be used to drive an appropriate amount based upon thepressure on the driven side. For example, when a 125 ml syringe having aflat plunger face sold by the present assignee is driven at 50 PSI, theundriven side should be driven approximately 1.72 ml to compensate formovement of fluid due to elasticity. With this syringe, at 100 PSI, thedriven amount is 2.28 ml, at 150 PSI, 3.45 ml, at 200 PSI, 4.32 ml, at250 PSI, 5.37 ml, and at 300 PSI, 6.78 ml. Other syringes will haveother characteristic values at various pressures. In a combinedopen/closed loop approach, the initial displacement applied to theundriven side upon initiation of the injection may be obtained frommeasured typical values, after which a closed-loop control may beinitiated to maintain an equilibrated pressure between the driven andundriven sides and/or zero flow rate on the undriven side.

Previous injector powerheads for contrast media injectors have includedmechanisms to move the motor powered syringe ram back and forthautomatically. These mechanisms have included levers, membrane key pads,push button or toggle switches, magnets and Hall-effect sensors, etc. Inall such instances, though, these mechanism were part of the powerheadof the injector.

Embodiments of the present invention relate to a remote controlpowerhead in which the control means for effecting movement of thesyringe ram is locate remotely from the powerhead. Such a remote controlwill allow an operator greater flexibility in location during certaininjector operations and protocols.

FIG. 7 illustrates one simple remote control 710 that is sized to fit inan operator's hand. The remote control emits a signal from a transmitter712 that is received at a receiver 708 at the powerhead. Within thepowerhead, the signal is converted for use by the motor controlcircuitry 702 to effect movement of the syringe ram 706 through themotor drive 704. The motor drive 704 and syringe ram 706 operate similarto conventional powerheads except that in addition to receiving inputfrom local controls, the input from the receiver 708 is considered aswell. The exemplary remote control 710 includes two buttons 714, 716.One button 714 extends the ram 706 towards the front of the syringe andthe other button 716 retracts the ram 706 from the front of the syringe.This particular remote control 710 permits one-handed operation becauseof its size and button placement.

One of ordinary skill will recognize that such a remote control 710 caninclude a variety of functions, have a variety of physical form factors,and include various numbers of buttons and knobs, without departing fromthe scope of the present invention. For example, a potentiometer (linearor rotary) may be used to remotely control the ram movement at a fixedspeed. Alternatively, a pressure sensitive switch may be utilized thatpermits control of the ram movement but changes its speed depending onthe pressure supplied.

The frequency at which the remote control and the powerhead communicateis not a material constraint of the present invention which explicitlycontemplates UHF, VHF, RF, infrared, ultrasonic, etc. as exemplarycommunication modes. Because the remote control may have a tendency tobe separated from the general vicinity of the powerhead, a physicaltether 720 may be provided that limits the removal of the remote controlfrom the powerhead. Accordingly, this tether may also act as acommunications path in certain embodiments such that the remote controlis not a wireless device but is coupled to the powerhead via a physicalcable.

During venous procedures utilizing power injectors, the contrast mediaor imaging agent is sometimes unintentionally injected into the tissuesurrounding a patient's vein. This is generally referred to asextravasation and is considered a hazard. It is commonly caused by theoperator missing the patient's vein entirely while inserting a catheter;piercing through the vein into surrounding tissue; or injecting at aflow rate that punctures the wall of the vein.

There are common techniques used by operators to detect or preventextravasation but these are not always 100% effective. When using a dualhead injector, one common technique is to perform a patency test byfirst injecting saline into a patient's vein while observing for skinswelling. This may be done manually or as part of a stored protocol.While effective in some cases, the saline may not be injected at a flowrate and volume that adequately simulates the injection protocol. Thus,the actual imaging agent injection may extravasate even if the salineinjection did not.

Embodiments of the present invention relate to a dual head powerinjector that includes in its software, one or more routines that assistan operator in selecting an optimum flow rate and volume during thesaline injection test portion of a patency test. The patency testinterface screen will suggest to the operator flow rate and/or volumevalues that are based on the selected protocol that provide a simulationthat is substantially similar imaging injection that is to follow. Thisadditional functionality may be included via a separate dedicateddisplay on the powerhead, or console, or may be one of the many menuscreens typically presented to an operator through the general interfacescreen. Also, the software may automatically set the flow rate andvolume or permit the user to set, or modify, the values after seeing thesuggested values. Certain safeguards may be included such that a patencycheck may not be performed until a protocol is enabled or until a manualpurge has been completed. Also, the patency check may include averification that enough saline remains available before proceeding withthe patency check.

In general, the principles of the present invention can be implementedaccording to an exemplary algorithm depicted in the flowchart of FIG.11. In step 1102 an injection protocol is selected and enabled. Beforethe protocol is performed, however, the operator may want to perform apatency check, and activates the patency check (step 1108). In anexemplary embodiment, the user indicates desire to perform a patencycheck by pressing and holding the expel button for the saline syringefor a given period of time, although numerous other interfacemethodologies may be used to permit the user to initiate a patencycheck. As shown in the flow chart, the specific methodology discussedhere requires that the operator press a button for more than thethreshold time, thus ensuring that a patency check is notunintentionally initiated. If the button is released too early, nopatency check is performed, but may be re-initiated as illustrated atstep 1108.

In the described embodiment, the software performs an optional check instep 1110 to determine if adequate fluid exists to perform the patencycheck and the selected protocol. If there is not adequate fluid, theprocess stops. However, if there is sufficient fluid, then the patencycheck may be executed in step 1112.

Based on the selected protocol, an operator is presented interfaceoptions to set up the patency check. These options derive from theexisting protocol or from settings made by the user. As seen at step1114, a volume for the patency check is derived from a factory default,or a historical volume used for previous patency checks. As shown atstep 1116, the user has the opportunity to change the volume if desired.If, so, then the volume value is changed in step 1118. As seen at step1120, a flow rate is also selected for the patency check. Again, thiscould be based on the protocol, a default value or historical data. Inthe described embodiment, the default flow rate is selected to be themaximum flow rate on the “A” or “B” sides of the injector, so that thepatency check verifies the lack of extravasation at the largest flowrate that will be required. Here again, the user is provided the optionof changing the patency check derivation in step 1122—if desired theuser may choose the “A” side flow rate or maximum “A” side flow rate, orthe “B” side flow rate or maximum “B” side flow rate, in step 1124.

Once the user has been presented with patency check settings (e.g., in asetup screen displayed immediately after step 1110), the user mayexecute the patency check in step 1112. Assuming no extravasation isevident, the operator would typically proceed to enable the protocol instep 1102, at which point the injector awaits a “start” indication fromthe operator in step 1104, upon which the protocol is executed in step1106. If there is extravasation seen during the patency check, this maybe remedied, and another patency check performed.

Referring now to FIG. 12, a test injection methodology can be described.To perform a test injection, in step 1202 the operator selects a testinjection when configuring an injection protocol, such as by depressingthe “test injection” key in the protocol setup screen shown in FIG. 6.Once a test injection is selected, the test injection/protocol setupscreen is displayed, as shown in FIG. 13. On that screen, it can be seenthat in addition to the injection protocol parameters displayed as shownin FIG. 6, test injection parameters are displayed in an area 1302.These parameters include parameters identifying the flow rate and totalvolume of a test injection.

As seen in FIG. 12, the values for the flow rate and volume of a testinjection are generated using the stored information and protocolparameters that have already been set by the user. Specifically, as seenat 1208, a factory default value (e.g., 10 ml) may be initially used asthe volume of a test injection, or the volume used in a prior testinjection may be used. The volume setting created is a default, but canbe changed. As seen in FIG. 13 the test injection flow rate and volumesettings are shown in buttons on the screen, which may be touched toenable adjustment with a slider bar or other graphical control as isshown in FIG. 6. Thus, in step 1210 of FIG. 12 the user may take actionto change the volume settings and in step 1212, make a desired change togenerate the final volume settings for the test injection.

Similarly, in step 1214, a default flow rate is created for the testinjection based upon the initial flow rate and side (“A” or “B”) used inthe already programmed protocol. These values are defaults and, asbefore, in step 1216 the user may take action to change the flow rate instep 1218. After making changes or accepting the defaults, the flow ratesettings are determined.

In addition to the above adjustments, the user may change the head usedby touching the button in the “Side” column on the graphical display, asis done in the interface of FIG. 6 when a test injection is notselected.

Initially, a test injection may include only injection from one side ofthe injector, e.g., the “A” side or a side that has been identified ascarrying contrast media. However, a test injection may also use bothsides, e.g., to inject a bolus of contrast media followed by a salineflush so as to create a “packet” of contrast media surrounded by salinefluid. Or the test injection may be done only with contrast media, atthe operator's discretion. Whether both sides are used may be determinedfrom whether both sides are used in the subsequent protocol, and/or onvarious default parameters. The injector may include default settingscreens for identifying the default use of injection heads as well asmethods for deriving volumes and/or flow rates from a current protocolor prior test injections, allowing operator configuration of theinjector's behavior.

After the parameters of a test injection are set in the manner notedabove, in step 1220 the injector evaluates those parameters in anoptional step to determine whether there is adequate volume forexecution of both the test injection and the subsequent protocol. Ifthere is not adequate volume then in step 1222 the operator may bewarned of the insufficiency, for example by indicating in a red color orby blinking colors, or both, of the part of the injection for whichthere will be insufficient volume of fluid available. This warning isparticularly useful in that it avoids a circumstance where the operatormust return to the imaging room after a test injection or a partiallycompleted injection, to refill syringes and remove air, potentiallywasting contrast media and substantial time in re-work. In acircumstance of insufficient volume, the injector may prevent the testinjection, or may allow operator override of the warning, as may besuitable for a given clinical setting. The response of the injector mayalso be different based upon whether there is inadequate contrast media(which is more likely to have adverse effects on imaging) or inadequatesaline (which is less likely to have such effects).

After passing through the optional step 1220, the user may enable theinjector by pressing the enable key 1304 shown in FIG. 13 (if notpreviously enabled), which leads to step 1224 shown in FIG. 12. At thispoint, the test injection may be initiated by the operator pressing thestart button in step 1224. When the start button is pressed, then instep 1226 the test injection step(s) are executed as set forth on thesetup screen shown in FIG. 13. Thereafter, the operator evaluates thetest injection and, for example, the quality of imaging achieved withthe set flow rate and/or the scan delay from the time of the injectionto the appearance of contrast media on the scanner, and in step 1228 mayadjust injection parameters for the injection protocol in response. Ifthere is a pressure limit hit during the test injection, then theinjector may disable, and provide a warning that a pressure limit washit, so that the operator is spurred to make modifications through step1228 before re-enabling the injection prior to execution of theprotocol. Thereafter, the user may depress the start button in step 1230to cause the injector to execute the injection protocol in step 1232.

It will be appreciated that one use of the test injection may be toidentify the time required for contrast media to reach a particular partof the patient's body where it can be effectively imaged, so that, forexample, the technician may set a scan delay time defining when scanningshould commence after an injection has begun. To facilitate thisactivity by the technician, an injector in accordance with principles ofthe present invention may incorporate a number of features that workwith the test injection function to ensure an accurate scan delaycalculation.

First, the injector may be usable to compute a scan delay time from (a.)the reconstruction time of the scanner being used and (b.) the observedtime delay from the beginning of injection to the appearance of contrastmedia on the scanner display. The reconstruction time of the scannermust be subtracted from the observed time delay to identify an accuratescan delay time, since observation of contrast on the scanner will beafter contrast has actually arrived at the location seen on the screen,due to reconstruction delay. Thus, to facilitate the determination of anaccurate scan delay, the injector may facilitate computation of thedifference of the observed time difference and scanner reconstructiontime. An injector configured to compute this difference may also beconfigured to assist in measuring the time delay between the start ofinjection and observation of contrast, for example by measuring anelapsed time between the start of an injection and a input by thetechnician that contrast is being observed on the scanner display.

Second, the injector may assist in the repeatability of injectionactivity by including functionality to return the state of the Y or Vtubing connected to the injector to a predetermined state. For example,the desired initial state prior to an injection may be that the tubing,through to the injection site, be filled with saline. This initial stateis a potentially important part of the timing that will be achieved inan injection, as the initial flow of contrast into the injection sitemay be delayed by several seconds corresponding to the time to flushsaline out of the tubing and contrast into the tubing. Alternatively,the initial state prior to an injection may be that the tubing is filledwith contrast, or some part of the tubing has saline and some part hascontrast. Those initial conditions will have different correspondingbehaviors in the timing of the start of an injection.

An injection in accord with principles of the present invention maycontain a feature in which the main single line section of the Y or Vtubing is prefilled with contrast, saline, or any predeterminedcombination of the two, according to the settings of the injector and/orpreferences of the operator. To implement this feature the injectorwould contain information about the specific tubing used, the volume oftubing after the joint to a single tube, as well as the desired initialcondition. If the main single line section is no greater than 10 ml incapacity, then an initial fill of that section by a desired fluid may beassured by a push of 10 ml of the desired fluid as a final step prior toinitiation of the injection.

An injector implementing this initial condition function may follow atest injection as set forth in FIG. 12 by such a single push of salineor contrast, as desired, to return the injector to the desired initialcondition. Thus, for example, if a test injection involves a final stepthat is a contrast injection, and the desired initial condition is tohave the single main line flushed with saline, then after the testinjection the injector would automatically push saline to flush thesingle main line and return the injector to the desired initial state.The obverse activity could be performed where a test injection has afinal step that is a saline injection and the desired initial conditionis to fill the single main line with contrast.

It will be further appreciated that the desired initial condition for aninjection may be a parameter or may be deduced from the nature of theprotocol requested; e.g., in one embodiment it might be assumed that ifthe first injection step is contrast that the desired initial conditionis to have the single main line filled with saline fluid, and so proceedat the initialization of a test injection as well as in theinitialization of the injector after the test injection and prior toexecution of the programmed protocol.

While the present invention has been illustrated by a description ofvarious embodiments and while these embodiments have been described inconsiderable detail, it is not the intention of the applicants torestrict or in any way limit the scope of the appended claims to suchdetail. Additional advantages and modifications will readily appear tothose skilled in the art. The invention in its broader aspects istherefore not limited to the specific details, representative apparatusand method, and illustrative example shown and described. Accordingly,departures may be made from such details without departing from thespirit or scope of applicant's general inventive concept.

What is claimed is:
 1. A contrast media injector system comprising: apowerhead including a display screen; the powerhead configured tocontrol injection of a fluid from within a fluid container coupledthereto to a patient through tubing connected to the fluid container; afirst iconic graphical element within the display screen representingthe fluid container and the fluid therein, wherein a color of thegraphical element is selected based on an identity of the fluid; and asecond iconic graphical element within the display screen representingthe tubing and the fluid therein, wherein a color of the second iconicgraphical element is substantially identical to the color of the firsticonic graphical element, and wherein the second iconic graphicalelement extends from the first iconic graphical element on the displayscreen.
 2. The system of claim 1, wherein a color of the first iconicgraphical element representing the fluid container and the fluid isyellow if the fluid is saline.
 3. The system of claim 1, wherein a colorof the first iconic graphical element representing the fluid containerand the fluid is purple if the fluid is contrast media.
 4. The system ofclaim 1, wherein a color of the first iconic graphical elementrepresenting the fluid container and the fluid is black if the fluid isair.
 5. The system of claim 1, wherein the first iconic graphicalelement representing the fluid container and the fluid and the secondiconic graphical element representing the tubing indicate a level of thefluid within the fluid container and connected tubing, respectively. 6.The system of claim 1, wherein the powerhead is a dual head powerheadand the display screen includes the first iconic graphical element for afirst syringe connected thereto and a third iconic graphical element fora second syringe connected thereto, wherein a respective color for eachof the first and third iconic graphical elements is dependent on arespective fluid associated with each of the first and second syringes.7. The system of claim 6, further comprising respective first and secondtubing connected to the first and second syringes, the display screenincluding the second iconic graphical element for the first tubing and afourth iconic graphical element for the second tubing, wherein thesecond and fourth graphical elements are colored substantially similarto the color of the first and third iconic graphical elements,respectively, and wherein the fourth iconic graphical element extendsfrom the second iconic graphical element on the display screen.